The present invention relates to a gas injection apparatus and method for injecting a gas into a liquid, for instance oxygen into an aqueous gold slurry. More particularly, the present invention relates to such injection apparatus in which a stream of liquid is directed against a plate to produce a sheet-like turbulent flow regime having entrained gas bubbles which are discharged with the turbulent flow from a peripheral region of the plate.
There are many industrial applications in which gases are injected into liquids. An example of such an application is water aeration. In water aeration, bacteria are destroyed by injecting oxygen into the water. In another application, involving mineral processing, oxygen is injected into a gold slurry in order to meet the oxygen requirements or demand of gold slurries. In the gold slurry application, oxygen is injected into the gold slurry from a lance. Spargers are also used for this purpose.
The problem with prior art methods of oxygen injection is that a high enough dissolved oxygen content is not obtained because of mass transfer inefficiencies. For instance, bubbles of oxygen coalescence to produce large bubbles. The larger bubbles have less of a surface area per unit volume than the smaller bubbles and hence the concentration of oxygen within the liquid is lower than had the bubbles not coalesced.
As will be discussed, the present invention provides a gas dissolution apparatus and method in which such mass transfer inefficiencies are overcome by preventing large-scale coalescence. Such gas dissolution apparatus has particular application to an improved gold slurry treatment.